Surgical Correction of Sagittal Plane Deformity in Scheuermann's Kyphosis

Centre for Spinal Studies and Surgery
Queen's Medical Centre, University Hospital Nottingham, Nottingham, UK

PURPOSE:
Surgically treated Scheuermann's kyphosis cases have been reviewed to evaluate the factors affecting the degree of correction, loss of correction, and proximal and distal junctional kyphosis.

METHODS:
39 cases (24 male, 15 female) of Scheuermann's kyphosis, treated surgically to relieve persistent pain or progressive deformity, during 1992-1999, were reviewed. Median age at operation was 18 years (14-53). Mean preoperative kyphosis (Cobb angle) was 81° (65°-115°). The apex of the curve was at T-8 or higher in 20 cases, and at T-9 or lower in 19 cases. Flexible curves, which bend down to below 45° on hyperextension bending x-ray (n=12) had one-stage posterior surgery only, using segmental instrumentation. Rigid curves (>45° on bending films) had either thoracoscopic anterior release (n=17) or open anterior release (n=10), followed by posterior instrumentation (A-P).

RESULTS:
Mean follow-up was 45 months (26-140). The mean direct postoperative kyphosis was 47.2° (38°-75°), and mean loss of correction at final follow-up was 9.3° (0-17°). Kyphosis correction achieved at final follow-up ranged from 39% after posterior only surgery, to 42% after thoracoscopic A-P surgery, and 48% after open A-P surgery. Mean loss of correction was 12° after posterior only surgery, 9.5° after thoracoscopic A-P surgery, and 6° after open A-P surgery. 4 cases of open A-P surgery had additional anterior structural support with cages, before posterior instrumentation; a mean 55% kyphosis correction was achieved in this group, and there was no loss of correction. Younger cases, under 18 years (n=21) had significantly better kyphosis correction than the older age group (p<0.05). Four cases (10%) developed distal junctional kyphosis due to fusion short of the first lordotic segment; all of them had the apex below T-9. Six cases (15%) developed proximal junctional kyphosis; all of them had the apex above T-6. Complications included infection (4), pneumothorax (1), heamothorax (1), instrumentation failure (4 cases); 3 cases had persistent back pain.

CONCLUSIONS:
Combined anterior release and posterior surgery achieves and maintains better correction of Scheuermann's kyphosis. Anterior structural support prevents loss of correction. Proximal junctional kyphosis is more common in higher curves, and distal junctional kyphosis is more common in lower curves. Correction is better achieved in younger patients, but is not influenced by the location of the curve.